Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/56—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds
  • C07C45/57—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom
  • C07C45/58—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom in three-membered rings

Definitions

• the present invention relates to a process for the preparation of cyclic ketones by isomerization of the corresponding epoxides. More specifically, it relates to the rearrangement of the epoxide using an alkali or alkaline-earth halide in the presence of the a polar solvent.
• the isomerization of epoxides to the corresponding cyclic ketones is carried out in diethyl ether with anhydrous halides from group IIA and IIIA elements of the Periodic Table of Elements (designation corresponding to Chemical Abstracts), in particular with magnesium iodide and magnesium bromide. Following removal of the salts by means of a water bath, the ketones are obtained by distillation.
• reaction times for a conversion greater than 95% are from 15 to 70 hours;
• one the object of the present invention is a process for the preparation of cyclic ketones, which process is less time-consuming and can be carried out without risk and does not exhibit the aforementioned drawbacks.
• a cyclic ketone from a cyclic epoxide which comprises contacting a cyclic epoxide with an alkali or alkaline-earth halide in the presence of a polar solvent at a temperature ranging from about 120°-250° C., wherein the cyclic epoxide is unsubstituted or substituted with one or more C 1-5 alkyl groups, and the cyclic epoxide comprises 7-20 ring carbon atoms and it may contain up to 5 carbon-carbon multiple bonds.
• the invention relates to a process for the preparation of cyclic ketones having 7 to 20 ring carbon atoms, having 0 to 5 multiple bonds, and having a side chain, which consists of 0 to 5 carbon atoms, of the corresponding epoxide (oxiranes) which can be practically and easily obtained from cyclic olefins.
• the process involves the preparation of the following compounds: ##STR1## in which a, b, c, d, e, and f in each compound is selected in such a manner that the total number of ring carbon atoms ranges from 7 to 20 and R is a C 1-5 straight-chain or branched alkyl or alkenyl group such as for example H, CH 3 , C 2 H 5 , C 2 H 3 , C 3 H 7 , C 3 H 5 , C 4 H 9 , C 4 H 7 , C 5 H 11 or C 5 H 9 .
• ketones are, for example, useful intermediates in the preparation of lactams, amines, carboxylic acids and a large number of other compounds. Cyclic ketones having 15 to 17 carbon atoms are valuable for use in perfumes.
• epoxides ranging from 120° to 250° C., in particular from 150° to 200° C.
• epoxides can be rearranged to the corresponding ketones in a polar solvent in the presence of alkali halides or alkaline-earth halides in very good yields and that the work-up and recovery of the solvent and catalyst is possible in practical, easy process steps.
• Suitable solvents are polar, aprotic solvents, which can form a homogenous solution with the alkali or alkaline-earth halide salt and the substrate and which do not undergo any reaction with the epoxides and the ketones resulting therefrom.
• Suitable solvents include N,N'-disubstituted cyclic ureas, N-substituted lactams and N,N'-disubstituted acid amides.
• the solvent quantity should be from 20 to 300% by weight, in particular from 80 to 120% by weight, based on the quantity of epoxide.
• Suitable catalysts are alkali halides and alkaline-earth halides such as magnesium iodide and magnesium bromide, preferably, sodium iodide and lithium chloride. As a rule, no more than 7 hours are required for complete reaction.
• the halide salts are added in quantities ranging from 0.5 to 20% by weight, preferably from 2 to 7% by weight, based on the quantity of epoxide.
• the work-up is not complicated.
• the solvent is removed by means of distillation and the catalyst is filtered from the product ketone.
• the filtrate is washed with water and the dried. Catalyst and solvent are almost quantitatively recovered.
• the process of the invention has the following advantages:

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Catalysts (AREA)

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• 1987
  • 1987-12-24 DE DE19873744094 patent/DE3744094A1/de not_active Withdrawn
• 1988
  • 1988-09-14 US US07/244,070 patent/US4885397A/en not_active Expired - Fee Related
  • 1988-10-27 EP EP88117877A patent/EP0322537A3/de not_active Withdrawn
  • 1988-12-23 JP JP63323810A patent/JPH01203344A/ja active Pending

Patent Citations (6)

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